From: "Shevchenko, Andriy" <andriy.shevchenko@intel.com> To: "Zulkifli, Muhammad Husaini" <muhammad.husaini.zulkifli@intel.com> Cc: Linus Walleij <linus.walleij@linaro.org>, Ulf Hansson <ulf.hansson@linaro.org>, "Hunter, Adrian" <adrian.hunter@intel.com>, Michal Simek <michal.simek@xilinx.com>, linux-mmc <linux-mmc@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "Raja Subramanian, Lakshmi Bai" <lakshmi.bai.raja.subramanian@intel.com>, "Wan Mohamad, Wan Ahmad Zainie" <wan.ahmad.zainie.wan.mohamad@intel.com>, Mark Gross <mgross@linux.intel.com> Subject: Re: [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC Date: Thu, 3 Dec 2020 10:12:06 +0200 [thread overview] Message-ID: <20201203081206.GR4077@smile.fi.intel.com> (raw) In-Reply-To: <DM6PR11MB28767ED32E97BF93C5F3C7B4B8F20@DM6PR11MB2876.namprd11.prod.outlook.com> On Thu, Dec 03, 2020 at 09:10:14AM +0200, Zulkifli, Muhammad Husaini wrote: > >From: Linus Walleij <linus.walleij@linaro.org> > >Sent: Thursday, December 3, 2020 2:55 AM > >On Wed, Dec 2, 2020 at 8:04 AM <muhammad.husaini.zulkifli@intel.com> > >wrote: ... > >If it should use any abstraction it should be a selector regulator IMO and > >while that may seem overengineered it adds something because regulators > >are used in the MMC subsystem for vdd and vqmmc because we are handling > >the OCR mask with that and it can support any amount of present and future > >voltages for signal levels with that as well. Any future changes to how the > >different signal voltages are set or which voltages exist can then be done in > >that regulator driver. > > This is limitation of Keem Bay HW and I would say Keem Bay HW is somewhat > unique in the way of handling the IO bus line voltage. > SDcard does not have its own voltage regulator. > I created one function sdhci_arasan_keembay_io_line_supply_operation() in sdhci-of-arasan.c > to handle the vqmmc(io line supply operation) specific for Keem Bay SoC. > > For Keem Bay, to actually modelling this as regulator ,for vqmmc, , we need to handle 2 things: > 1) Output expander pins : using gpio regulator > 2) voltage rail : call keembay_io_rail_supplied_voltage() to handle the SMCC Arm. > > Other hardware might not need this as they might easily configure the vqmmc > hooked up to regulator. > > IMHO, we do not need to overengineered it to add custom selector > regulator just to suit this Keem Bay HW design. I guess Linus has a point. If it can be abstracted as selector regulator it will suits generic approach in the MMC code. And what is the problem to have two or more regulators? Or regulator hierarchy? -- With Best Regards, Andy Shevchenko
WARNING: multiple messages have this Message-ID (diff)
From: "Shevchenko, Andriy" <andriy.shevchenko@intel.com> To: "Zulkifli, Muhammad Husaini" <muhammad.husaini.zulkifli@intel.com> Cc: Ulf Hansson <ulf.hansson@linaro.org>, Mark Gross <mgross@linux.intel.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Linus Walleij <linus.walleij@linaro.org>, linux-mmc <linux-mmc@vger.kernel.org>, Michal Simek <michal.simek@xilinx.com>, "Hunter, Adrian" <adrian.hunter@intel.com>, "Raja Subramanian, Lakshmi Bai" <lakshmi.bai.raja.subramanian@intel.com>, "Wan Mohamad, Wan Ahmad Zainie" <wan.ahmad.zainie.wan.mohamad@intel.com>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC Date: Thu, 3 Dec 2020 10:12:06 +0200 [thread overview] Message-ID: <20201203081206.GR4077@smile.fi.intel.com> (raw) In-Reply-To: <DM6PR11MB28767ED32E97BF93C5F3C7B4B8F20@DM6PR11MB2876.namprd11.prod.outlook.com> On Thu, Dec 03, 2020 at 09:10:14AM +0200, Zulkifli, Muhammad Husaini wrote: > >From: Linus Walleij <linus.walleij@linaro.org> > >Sent: Thursday, December 3, 2020 2:55 AM > >On Wed, Dec 2, 2020 at 8:04 AM <muhammad.husaini.zulkifli@intel.com> > >wrote: ... > >If it should use any abstraction it should be a selector regulator IMO and > >while that may seem overengineered it adds something because regulators > >are used in the MMC subsystem for vdd and vqmmc because we are handling > >the OCR mask with that and it can support any amount of present and future > >voltages for signal levels with that as well. Any future changes to how the > >different signal voltages are set or which voltages exist can then be done in > >that regulator driver. > > This is limitation of Keem Bay HW and I would say Keem Bay HW is somewhat > unique in the way of handling the IO bus line voltage. > SDcard does not have its own voltage regulator. > I created one function sdhci_arasan_keembay_io_line_supply_operation() in sdhci-of-arasan.c > to handle the vqmmc(io line supply operation) specific for Keem Bay SoC. > > For Keem Bay, to actually modelling this as regulator ,for vqmmc, , we need to handle 2 things: > 1) Output expander pins : using gpio regulator > 2) voltage rail : call keembay_io_rail_supplied_voltage() to handle the SMCC Arm. > > Other hardware might not need this as they might easily configure the vqmmc > hooked up to regulator. > > IMHO, we do not need to overengineered it to add custom selector > regulator just to suit this Keem Bay HW design. I guess Linus has a point. If it can be abstracted as selector regulator it will suits generic approach in the MMC code. And what is the problem to have two or more regulators? Or regulator hierarchy? -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-03 8:11 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-02 15:02 [PATCH v6 0/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC muhammad.husaini.zulkifli 2020-12-02 15:02 ` muhammad.husaini.zulkifli 2020-12-02 10:53 ` Ulf Hansson 2020-12-02 10:53 ` Ulf Hansson 2020-12-02 12:25 ` Shevchenko, Andriy 2020-12-02 12:25 ` Shevchenko, Andriy 2020-12-02 12:41 ` Ulf Hansson 2020-12-02 12:41 ` Ulf Hansson 2020-12-02 13:10 ` Andy Shevchenko 2020-12-02 13:10 ` Andy Shevchenko 2020-12-02 14:10 ` Ulf Hansson 2020-12-02 14:10 ` Ulf Hansson 2020-12-02 14:34 ` Andy Shevchenko 2020-12-02 14:34 ` Andy Shevchenko 2020-12-02 14:38 ` Zulkifli, Muhammad Husaini 2020-12-02 14:38 ` Zulkifli, Muhammad Husaini 2020-12-02 15:02 ` [PATCH v6 1/4] mmc: sdhci-of-arasan: Add structure device pointer in probe func muhammad.husaini.zulkifli 2020-12-02 15:02 ` muhammad.husaini.zulkifli 2020-12-02 15:02 ` [PATCH v6 2/4] firmware: keembay: Add support for Trusted Firmware Service call muhammad.husaini.zulkifli 2020-12-02 15:02 ` muhammad.husaini.zulkifli 2020-12-02 15:02 ` [PATCH v6 3/4] dt-bindings: mmc: Add phys, vmmc and vqmmc supplies for Keem Bay SOC muhammad.husaini.zulkifli 2020-12-02 15:02 ` muhammad.husaini.zulkifli 2020-12-02 15:02 ` [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support " muhammad.husaini.zulkifli 2020-12-02 15:02 ` muhammad.husaini.zulkifli 2020-12-02 18:54 ` Linus Walleij 2020-12-02 18:54 ` Linus Walleij 2020-12-03 7:10 ` Zulkifli, Muhammad Husaini 2020-12-03 7:10 ` Zulkifli, Muhammad Husaini 2020-12-03 8:12 ` Shevchenko, Andriy [this message] 2020-12-03 8:12 ` Shevchenko, Andriy 2020-12-05 23:01 ` Linus Walleij 2020-12-05 23:01 ` Linus Walleij 2020-12-12 14:06 ` Zulkifli, Muhammad Husaini 2020-12-12 14:06 ` Zulkifli, Muhammad Husaini
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